1. Technical Field of the Invention
This invention relates to telephone cable closures and, in particular, to apparatus for converting a ready access cable closure to a limited access configuration.
2. Description of the Prior Art
The vast majority of cable closures currently in use in the telecommunications industry are of a ready access type. Because of this ready access feature the cross connection wiring in these closures, while initially fairly neat and orderly, very quickly becomes a virtual rat's nest. In this condition additional entries into the closure quite frequently disrupt various cross connections and individual conductors are subject to damage by a craftsperson.
One example of this type of telephone cable closure is disclosed in C. C. Connell, U.S. Pat. No. 3,991,264 issued Nov. 9, 1976. Connell discloses a terminal box for use with telephone cable systems which includes a housing formed of geometrically identical channels interfitted by tongue and groove edge portions. Vertical brackets within the housing are movable along U-shaped horizontal supports to permit an increase in spacing between terminal blocks when making electrical connections. Individual conductor pairs in the cables terminated in the Connell closure are accessible to a craftsperson.
Another example of this type of terminal enclosure is disclosed in D. L. P. Hamilton, U.S. Pat. No. Re. 27,746 issued Aug. 28, 1973. Hamilton discloses a terminal chamber used for buried cable installations which is compartmented by plate-like supporting and partition members. The partition members carry spliced conductors. An unassigned conductor loop is secured to and overlies its front face. Another loop of unassigned conductors lies behind the partition member. Similar to Connell, the Hamilton closure does not preclude access to the unassigned conductors. Moreover, in Hamilton the cable ground sheaths are rigidly fastened to the closure.
An even further illustration of closures of the type under discussion is contained in R. G. Baumgartner, U.S. Pat. No. Re. 27,898 issued Jan. 22, 1974. Baumgartner relates to a pedestal-type telephone cable closure which comprises a base and an upper housing of like cross section. The base is mounted on a channel driven into the ground. Cables are led in through the base portion and supported on a bonding clamp that also contacts the metallic shield of the cable. A center partition in the upper housing physically segregates the pairs to which service wire splices are to be made. Similar to the other references, the Baumgartner closure does not restrict access to certain ones of the conductor pairs. Furthermore, as noted previously, the cables are supported by a rigid ground bonding arrangement.